Electron discharge device utilizing cavity resonators



Feb. 8, 1949. L'. s. NERGAARD ELECTRON DISCHARGE DEVICE UTILIZING CAVITY RESONATORS 3 Sheets-Sheet l willIllllnllllllllllllllm 54 64A fifi ,.z.`

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y f Cttormg MMA Filed Dec. 3l, 1945 l ivi Feb. 8, 1949. s. NERGAARD 2,461,125

K ELECTRON DISCHARGE DEVICE UTILIZING CAVITY RESONATORS LEDN 5. NEREHHRD Gttorneg L. S- NERGAARD ELECTRON DISCHARGE DEVICE UTILIZING Feb. 8, 1949.

CAVITY RESONATORS 3 Sheets-Sheerl 5 Filed Deo. 3l, 1945 inventor LEUN 5. NERGHHRD E www@ Gttorneg Patented Feb. 8, 1949 UNITED S-TAT`ll`:".,-S PATE OFFICE VELECT-RON` DISCHARGE DEV ICE UTILIZIN'G' CAVITY RESONATORS Y `Eicon S. Nergaard', Princeton, N. J., assignor toy RadioCcrporation-of America, a corporation-f 1 Delaware Application Decemtersl, 1943, seriai'No; 516,388

23 Claims..

A' further object of my'invention is to provide such a device having a low internalreactance which permits the use of a larger externalv circuit, that is ad'evicewhich Williunction athigher frequencies with an external circuit and thus permit tuning over a considerable range.

A more. specie object of my invention. is. to provide an electron discharge device in which the electrodes although closely spaced are. rmly and@ -rigidly supported with respectto each other.

Another specic object of'my invention. is to provide an electron discharge device in which the. anode forms part of the tube envelope andin which the anode-to-envelope seal is protected against electron bombardment.

Afurther object 'of my invention is to provide an electron discharge 'device having electrodeV leads and vsupports which Will merge into high irequency circuits ofthe 4cavity resonator type so that the internal reactances may be coupled smoothly to the. external reactances'which complete the circuit. and thus reduce radio frequency losses andl spurious modes of oscilla-tion to a minimum.

Another specic obj-ect of. my invention is to provide ari-electron discharge device having ai.

cathode support andzlead and a cooperating protectingsleeve'which also acts as'acathoderterrnih nallv permitting ready connection toga transmission line and receptionof the electron discharge device in any angular positiony in a: circuit.

A further objectof my .invention is. to. provide aterminalandshieldiior the cathode lead which facilitates incorporation of the electron dis-charge device into a cavity resonator circuitof'the coaxial line type. Y L

Another specific objectl V0f 'my invention is tio provide a cathode which ywill promote heater power economy.

A-still further object of my 'invention is tol'prcvide a-l'eadi andrsup-port for: thefc'athodeof 'an electrondischarge devicef ofthe` type' described',

which reduces the num-ber of leadsfor th'ecath-fy ode, lowers the radio` frequency losses, reduces the number of 'parts required andA makes `possible theuse of a simple tip-off' after exhaust.

A further object of my invention is to provide. an electron dischargev device andi associatedi'circuit having an improved" coupling loopiffor*prot-'-r viding feedback when the-device is toact ani oscillator.

A further'vob'ject of my invention-istoprcvide a cavity resonator circuitinwhichfthefcircuit has' largedimensions while permitting operation' fat? very high frequencies. n

Another' object of my invention isf toprovide: an electron discharge device and associated-cire cuits conrprisingy cavity resonators which providey a novel method of introducing biasing 'voltageson the electrodes enclosed within the-cavity res-A cna-tors.

A still further object of my invention iste-provide a load coupling system which veliminateslarge grid2 swings upon removal ofthe loa'df thusvl reducing chances of injury tothe grid-electrode'.

, A furtherobject of my inventionis to provide Y improved means for connecting the'terminals ofdevice to' a cavi-ty resona?v ticularity'irrthe-4 appended' claims, but the inven-r tion itself will pest be understoodv loyV reference to the followingl description taken inv connection'- Wi-th the-accompanyingdrawing'in which Figure*` Figure `1, Figure' 4 is an' enlarged 'lon-gitudinal-sec-- tion of an electrondischarge'devi'ce'utilizingthe apparatus shown'i'n FigureA 1', Figure 5"*is` aschematievr diagram ofV thel ultrahigh frequency'ap'-v paratus made according to Imy invention and shown inV Figure 1, Figure''is a longi-tudirralmsection of aV modification ofthe ultra high frequency@ apparatus shovvnin Figure 1, Figure 7 -i'sa'tran's'everse `sectional detailutilizedlinFigureB-andFigaure Sii-s azsectiontaken:alongthezlinevvlle-m off Figure 11'. Y l f The ultra high frequency apparatus made according to my invention and shown in Figure 1 consists of a specially designed triode electron discharge device specially adapted and designed to cooperate with cavi-ty resonator type circuits. Briefly the electron discharge device comprises essentially a cathode, grid and anode of the coaxial type, the anode forming part of the tube envelope. The grid and cathode are provided with specially designed terminals cooperating with and merging into the circuits proper. Connected between the grid and cathode isa coaxial line type resonator which provides the input circuit and coupled between the anode and grid is another coaxial line resonator of the half-wave open line type which provides the output circuit. The input resonator is tuned by means of a specially designed tuning condenser and energy is taken from the input circuit. A specially designed coupling loop couples the input and output resonators and is provided with means for tuning the loop to increase the eiiiciency of operation. In accordance with my invention high voltage is applied to the anode by means of a novel type probe.

The electron discharge device per se wiil be described before the apparatus as a Whole. Referring to Figure 4 an electron discharge device made according to my invention includes the inverted cup-shaped cathode H) provided with the heater II. A cup-shaped grid comprising a cap I2' and grid wires- I2 encloses the cathode and is coaxial therewith. An inverted cup-shaped anode I3, preferably formed from a copper block, encloses the cathode and grid and is coaxial with the latter two electrodes. For cooling purposes radiating nsare fastened, preferably by cadmium soldering to the anode block.

The grid is supported on a cone-shaped supporting member I 5 secured to the collar I6, which is provided with oppositely directed flanges I6' and |65'. Tlhe anode is provided with a ring- Llike sealing member I1 of inverted U-shaped transverse section. Sealed between the outer leg of the member I1 and the flange I6 is the insulating collar I8 preferably of glass. The cathode is supported on a tubular member I9 by means of the fingers 2U sealed between the cup-shaped member I9 and the closure member 2 I of the cathode. These fingers reduce the heat conduction from the cathode to the cathode support I9, at the same time providing rigid support for maintaining proper spacing between the cathode and grid. One end of the cathodeh-eater II is electrically connected to the cathode'cup I0 and the other provided with a lead 22 sealed through the end of the tubular member I9 by insulating seal 23. The tubular member I9 'is in turn hermetically sealed to the flange IB" by means of seal 24 of insulating mate-rial, preferably glass. The collar I6 is in turnV provided with a radially extending transverse flange 25 for purposes tobe described. Agetter element 2B is connected between the tubular member I9 and the lead 26 sealed through the endv of the tubular member losses are reduced. Because of the cone support great lateral stability of the grid results and a reduction in cathode-to-grid capacity results. Further stability is insured by the use of the element II extending through the top of the grid but insulated therefrom by means of the tubular member 3U. The element II' also supports the element 29 which 4may be utilized to increase the cathode-anode capacity for feedback purposes if desired. Element. 29 could also be eliminated and all of the desired feedback obtained in a manner to be described. Because of the cathode and 4grid supports by means of the cone and tubular member I9, lower radio frequency losses occur andthe result in mechanical assembly becomes quite simple. This construction also reduces the number of parts necessary for the assembly. The use of the cylindrical cathode lead I9 reduces the need for a great many leads through a glass stem and press and results in considerably less loss of radio frequency power. It also reduces the number of parts necessary for a cathode assembly and permits the use of a copper tip-off if desired.

The cathode cylinder is extended with a copper thimble or elongated cup-shaped member 3I. This member slides over and is secured to the cathode vsupport I9 and is provided with slots 32 and 33 for receiving the seals 2'I-23. The heater lead 22 is extended by means of the conductor 3S to the jack pin 34 insulated from member 3| by means of insulator collar 35. This thimble results in the protection of the exhaust tubulation and heater and getter leads, provides a cathode terminal which can be plugged into an appropriate socket in the transmission line and brings the heater lead out on the axis of symmetry so that the tube can be plugged into the circuit without reference to its angular position.

The assembled high frequency apparatus for generating an ultra high frequency power output and utilizing an electron discharge device of the type shown in Figure 4, is shown in Figure 1. The input circuit is of the coaxial line cavity resonator type coupled between the grid and the cathode, the end removed from the grid and cathode being closed.

This circuit comprises an outer tubular member 49 and inner tubular member 4I electrically |connected together and closed by means of the conducting disc 42. Transverse disc 43 is electrically and mechanically secured to the tubular member 40 and is provided with a shoulder or shelf 44 as shown in Figures l and 8 for receiving the grid ring 25 of the tube.

As best shown in Figure 8, supported on the member 43 are a plurality of sliding clamps 45, 49, 41 and 48 which can be slid transversely of the longitudinal axis of the electron discharge device to secure the grid ring to this member. They are slidably retained by means of the screw elements 49 which can be tightened when the grid ring is in place. Thus there is a direct electrical connection between the outside tubular member 49 and the grid, permitting the grid to be operated at yground potential. also gives good thermal contact to the grid flange, thus reducing the grid temperature. The cathode is capacitlvely coupled to the inner tubular member. Mounted within the inner tubular member 4I is theY tubular member 59, preferably of mica and a second tubular member 5I, which is conducting and provided with a cup-shaped portion 54 having spring :lingers 52 thereon engaging the outersurfaces of the Vcathode thimble 3l. This This arrangement l aapaiuveiy couples the eenieder@ conductors 55 and 56. The conduct'rii' elctridllyconectedto inner tubular member 5I in til'lrvidig a; Circuit tOIlt-r side ofy the Bathde He er through fingers 52, cathodev thimble 3i,

ath deieaa' and support r9, 1:0y the ribbonuike Supports Ztl, to one side of the cathode-back th''glif tlie cathode heater l-I, conductor' 22,

conductor S, pinV 3'4, jack 53, which is'in'sulating-v lir suppertedE by insulation 54' within the cup` Tlietankf circuit coupled betweenthe grid and,

-ndeis f the coaxial Half Wave' Open lille type andin-cludes the' inner Atubular member ll of cup-shape and securedfto the anode radiator Ey i'e'ans' of screw 5 i and `provided With curvedinlpil" for' 'reducing corona los-ses. The outer tLi-bula'r'nember `Elf'is mechanically and electrithus reduces the possibility of yserious voltage brealdown Aproblems which would occur with s 'rifal siecavit'y resonators maintainedto-operV etere example, at frequencies vhigher than 60o Ijelbls v While tlie apparatus could be operated asan afmpliifier, ljprfer to utilize itl as an oscillator' afnjdfor this purpose I provide the member 4'3 with* an aperture '4'3" to permit the use of a cou'- pling'loop'consisting of tubular element 'Iii and tubular element "il, in which is tel'escopically supported the u-siiaped member 12, lune iength f o f'whjich` can be varied to determinethe amount off`co`upl'in'g'desi`red. The portion of the element rr'withi'n kthe anode tank cireuu is formed as shown at 't3 to reduce sharp corners and'remove theloop'as far as possible from the high voltage eem of the amide.v

Injrder to tune out the 'reactance of the coupling loops l provide a tuning stub consisting` of the inner conductor l!! and the outer tubular r'remb'er T5 with a tuning ring operated by' ri'e ris of the operating. handle 11. This `i`ricreases the povve'r output and eciency Considerably. The equivalent electrical circuit of the coupling loop and tuning stub and the relationship tothe circuit is shown in Figure 3, the same nurieial'sbeihg utilized to indicate the saine elemerits sh'ovvn in Figure 1. This tuning stub is not part. of my'invention but is described and claimed ip 'a depending application of Robert P.L Stone,

Serial No. 547,190, led July 29, 1944, andas-l si'g'ned t'o the same assignee as the presentv invention.

In orderto tune the input circuit I provide a tunig'fcndenser 52 in the form of a disc or plate having arounde'd periphery in order to avoid sharp edges in the high frequency field. This Yeliminates the corona which is experienced When-- ever. sharp. edges arenus'ed between elementsat high irequencypotential differences. This `tun-- ing vcondenser plate is slidable along the inner tubular member 4I and is operated bya gear box mechanismindicated generally atr. Aeshaftl is rotatedeby-ineansof knob65 Which infturn ro-A tetes a'gear" G4 coupled "tor the gears 66 and* BT Theron-tout staken from the input resonator By assessor uieeoaxiai 10aa une A.51;53, the ijn-1- nrebduetbr :51 Veontactirlg tubular member-rlo'i tHe-inputresonator;

order to" cool" the vradiator and tliemseals''of the e-iectr'oedisearse device, a sint* as'l 'is-ferai video" infin outer conductores'.

Figure' 5 a schematic' fdiag'ranrishowin 'he' voltagesourcS-and tlemethod'of applyin ai pulse voltage to the anode for controlling oscilla`` t'ion-l of thejfapparatus rad'e` `a'ccird'irlg tol n'y' invention. lroithe' cathode heater vvI provide4 transformer 8-0 ywhiclrls electrically"connected to. thec Ahodejheater leads. The'cavltyresonators roundedby niens'bf"tlieconductor 8T and',

tween aufde and' gridi'sagaiii' offrire, axial uetype; 'gridring' is again clamped bymearis fisli'dnig eiafnp's as' to ameme'r su closing olie 'df'ftl' caLXal linek CiIC'lii-t coli-pled bei ifi'tl atll'de and grid, this circuit cmpri- Iig' tleutr tubular I'nmber fndtheillner tubular nirlnbr M ',Y the inner cathode vheater lead'fpin .321' being received WWithin a jack insulat-v inlyf 'supportedfby means ofthe insulating support member-54'. Tuning .of the input circuit isv accomplished by means ofthe shorting ring 6"'2' oeratadtyfmean-s er handles ss'ana se'. the cathode heater current being supplied by means of leads 5`5 -56 i the same manneras shown-in Figure .1. aeitiidfjllat'e 'member yil!) and ring member 9 4'l and the ccllarv 9'2 providing a cavity'reson'atr of' drum shape. An anode flange I3 is'c'lam'ped to thetop electrode of the jplate condenser. The plate condenser 11s p osiuoed'lbetween the' niemloerJV 92 and"tlie` plate "ge 'l'fa'nd comprises the twoV ele`ctrodes`93 and -s'eparated'by the meinber '9|' of'rnic'a. Themember' 90 may comprise' mica jdiscs'ihalvihg' graded annular rings.- of silverV to ldi"sifiilujje the electric 'eldun'ifor'mly and may be coated with a layer of titanium oxide salve` tov eliminate sparking andiburning `between sls1eets.--v Fill'ets of ytitaniunfi oxide salve are made around thezedges; ofrthe electrodes to eliminate corona-inf thefoondenser. v

eque'iicy 'apparatus shown 4in Figure 1 'and f y r ori'ator'circuit connected beg The output resonator includes theV The output is taken from the tank by means of the coupling loop95 forming the inner conductor of the coaxial output line, the outer conductor of which is tubular member 9B.

In accordance with my invention feedback is obtained by tapping a line 9'! on to the output line 95 through a slot in the outer conductor 96 of the output line. The feedback line is carried in a channel 99 to prevent radiation down to an appropriate place on the cathode line. Here itis connected to slide tap 98 on the cathode` line through slot 40" `in the outer conductor 40. Feedback is varied by sliding thetap.`

The feedback is taken on the output line side ofthe coupling loop. The usual feedback systems are such that ifa load is removed from the oscillator the grid swing increases. In many cases this swing increase is sufficient to injure the grid. This is particularly apt to happen when making adjustments of load coupling, If feedback is taken from the output line on the load side of the load adjusting means, this diiliculty is completely eliminated. Then when the load coupling is decreased the feedback also decreases and the grid swing is reduced instead of increased as in the usual arrangements. The arrangement described was found byactual test to bemost satisfactory.

The anode is cooled by an air blast on the radiator, which is one of the'ttings on the tube.

The member 92 is provided .with tubular member l extending therethrough and provided with apertures, such as IDI and |02 as shown in Figure 7. The glass work within the output cavity resonator is cooled by air jets diametrically Y lies. Apparatus of the .type described above is operated successfully at 600 megacycles with over 10i) kilowatt output when pulse-operated. Also 300 watts continuous wave with D. C. applied.

All of the features pointed out above as desirable have been included in the apparatus made according to my invention and described above.

While I have indicated the` preferred embodiments ci my invention of which I am now aware and have also indicated only one specic application for which my invention may be employed, it will be apparent that my invention is by no means limited to the exact forms illustrated or the use indicated, but that many variations may be made in the particular structure used and the purpose for which itis employed without departing from the scope of my invention as set forth in the appended claims,

What I claim as new is:

1. An electron Vdischarge device having a cathode, grid and anode, a cavity resonator coupled between said anode and said grid and including` an inner conductor coupled to said anode, andV a coaxial outer tubular member having one end coupled to said gridsaid outer tubular member being open at its free end and a cavity resonator coupled between said cathode and grid, and a voltage lead extending into the Ycavity resonator coupled between said anode and said grid, said voltage lead including a tubular member having a coaxial conductor and an insulating sleeve posilar member, the end of said lead contacting said anode comprising a probe mechanically biased against the anode.

2. An electron discharge device including a cathode, Vgrid and anode, a resonator coupled between said grid and anode and comprising a pair of coaxialtubular members, the tubular member connectedv toY said anode being of shorter axial length than the other tubular member, a cavity resonator coupled between said grid and said cathode, and a coupling device having a loop within said cathode-grid cavity resonator and a loop in said grid-anode resonator, said last mentioned loop having only rounded corners exposed to'said anode and terminating on the inner Wall of the outer tubular member.

. 3. An electron discharge device including a cathode, grid and anode, a cavity resonator coupled between said grid and anode, a cavity resonator coupled between said grid and said cathode, and a coupling device having a loop within said cathode-grid cavity resonator and a loop in said grid-anode resonator, said last mentioned loop having only rounded corners exposed to said anode and terminating on the inner wall of the resonator remote from said anode, the loop within said cathode-grid cavity resonator being adjustable.

4. An electron discharge device including a cathode, grid and anode, a resonator coupled between said grid and anode and comprising a pair of coaxial tubular members, the tubular member connected to said anode being of shorter axial length than said outer tubular member, a cavity resonator coupled between said grid and said cathode, and a coupling device having a loop within said grid-cathode resonator and a loop in said grid-anode resonator, said last mentioned loop having only rounded corners exposed to said anode and terminating on the inner wall of the outer tubular member, the cathode-grid cavity resonator comprising a coaxial line and a load line connected to the inner conductor of said cathode-grid cavity resonator and adjacent the end removed from said grid and cathode.

5. An electron disch-arge device including a cathode, grid and anode, a resonator coupled between said grid and anode and comprising a pair of coaxial tubular members, the tubular member connected to said anode being of shorter axial length than said outer tubular member, a cavityV resonator coupled between said grid and said cathode, and a coupling device having a loop within said cavity grid resonator and a loop in said grid-anode resonator, said last mentioned loop having only rounded corners exposed to said anodek and terminating on the inner wall of the outer tubular member, the cavity resonator connected between said grid and said cathode comprising a coaxial line cavity resonator, a load line connected to the inner conductor of the cathode-grid cavity resonator and adjacent the end removed from said grid and cathode, a voltage lead extending through said outer tubular member adjacent the end coupled to said grid and contacting said anode.

6. An electron discharge device including a cathode, grid and anode, and a cavity resonator coupled between said grid and anode and includinga pair of coaxial tubular members, the free ends of said tubular members being open, a cavity resonator coupled between said grid and said cathode and including a coaxial line resonator, saidfcathode being provided with a tubular lead.

ineir,1neroondnoinr 'of said oeaxial-linelreeonator `in udine aonnrsnaned1nen1ber:nrovided 4with ra .4.3111 outside of the tubular :oathode lead'anda Contact ity .of resilient contact ijlngers engagingthe on the linside of said cupfshaned member, and a nin on Said ,Cathode tubularlead. engaging Said contact, .said cup-shaped lniernlcer being 'insulatinglV-ysupportedby said inner conductorand providing capacity coupling between the cathode and said inner conduoor.

7. An electron discharge device having acath ode, grid and an anodey areeonator .eonnled between `Said anode .and grid and a cavity resonator v 1onr1ed:between Saiderid and Said oatnode. and `.1iriolirdiiie an elongated inner rneniloerlionnled to :said-onthodes and a inning oondenser nlatomovfable alonesaid inner tubular member and havine .a rounded rim Aspaced -from the Walls of Said cathode-*grid Yresonator- -81 An electron discharge device havin-g a cath- ,ode, :grid and an anode, resonator coupled between said anode and grid and a cavity resonator tcoupled betweensaid :gridand said cathode and `including an inner tubular member coupled to said cathode, Vand ya tuning Condenser plate movablealong said inner tubularmemberand having a rounded rim ,spaced from the Walls of said 'the1 position of said :tuning condenser plate along said vinner tubular member.

`9. An electron discharge device having a plua .ralitvfof electrodes, one o f said electrodes being provided with a fflange, a resonator coupled `to said electrodes and including a, member having vvank opening :through `which said electrondischarge dev-ice extends and a recessed shelf around said opening for receiving said flange, and nleansslid- .able vtoward and away from .said electron disan opening through which said electron discharge devi-ce .extends and a recessed shelf around said opening for receiving vsaid flange, and means including a .plurality of clamps slidable toward and away .from said electron discharge device for clamping said -flange against said shelf, and means vfor locking said clamps in clamping position.

l1. An electron discharge device having an anode vprovided with a closed end and an open end, a ring ,member of U-shaped transverse section sealed tothe outside of and adjacent the open end of said anode, a collar of insulating material having one fend sealed to the outer leg of the U -shaped ring member, a ring-like member having van outer flange .sealed tothe other end of said ,collar of insulating materiah an inner flange on said ring-like member and a tubular lead and support extending through said ring-like member and supportingan electrode Within said anode, and a seal between said inner flange and said tubular lead and support, the outer end of said'tubular lead and support being sealedoi.

1-2. An electron discharge device having an anode provided with a closed end and an'open end, a ring Kmembervof U-shaped transverse section sealed to the outside ofand adjacent the open end of Vsaid anode, -a `collar of insulating material ,having one .end sealed tothe outer leg ofithe all-shaped ring member, Va. ring-like I,mornafll Qlltrfl'lg ,Coaxafl'with Said U' cathode-grid resonator, andfmeans Vfor varying betiveen .the

Aonen .end fof 4seid anode, Qadollar-fof insnlat lead .-andsnnnort the outer end of said tubular :lead and support beineSealed on. .and .sa end noeiiiened between said atnode .fand anode and having an outwardly ilaredsupportings rtcon- .necte'dtoand sunported by i 1S.- An eleotrorl .sonargefdevroe haringen th a o1 ed endfand anonen Jaoeni the s material having oneendfsealed to the outer :les of the vu-,snanedring niemleena ring-,linemanber having an ,outer .danse sealed tothe other endof saidcollar ofL latingvmaterial, an anse on said ring-.like fmernloer :and a tu lead and support extending throughsaid like member and supporting anjelootrode within said anode, said tubular lead and support being sealed `to said inner flange.

14. An electron :discharge .device `ghaving :an

envelope, a cathode within saidlerivelopeaa ,-tllbll: `.lar klead .and support for ,said cathode-:sealed ythrough said envelope, apluralitv ofjconducting elements 4of ksmal-1 transarerse section connected between said :cathode and said ,tubular zleadand support, azheaterfforsaid cathode having Oneside .electrically connected to ssaid cathode, a. eleadex: tending Athrough ,said 'tubular lead and support and insulatingly sealed through said tubularlead and supporhlth'e other end .-of saidiheater being i connected `to `the ,lead extending through said tubular lead.

l5. An electron discharge device Vhaving an' envelope, a cathode .within .said envelope, .aotulou-i :lar =lead and support for Lsaid cathode sealed through saidlenvelope, a heater for-said cathode having one side .electrically'oonnected :to vsaid cathode, and the other-end vconnected `to v,a lead `extending through -said tubular flead andsupport and insulatinglyosealed through said-tubulartlead and support, an elongated cup-,shaped member Ihaving its open end telescoped with `the :tubular lead and support, a terminal in the rclosed :end

of said elongated cup-shaped member, said lead being connectedto Fsaid terminal.

v16. Anfelectron discharge device having a `cupshaped anode, a cathode Within said anode, va tubular lead and Asupport lfor said cathodeand sealed to said y anode to .provide an envelope, la heater for said cathode 'Shaving one side'electrically connected to said cathode, vand-theother end connected to a lead extending through said tubular lead and support and insulatingly sealed member and supporting a cathode within said anode, said tubular lead and support being sealed to said ring-like member, the outer end of said tubular lead and support being sealed off, a heater for said cathode having one end connected to said cathode and having a lead insulatingly sealed through the closed end of said tubular lead and support, an elongated cup-shaped tubular shield having its open end telescoped over the closed end of said tubular lead and support, and a terminal in the end of said shield, the heater lead being connected to said terminal.

18.1An electron discharge device having a cupshaped anode, a collar of insulating material having one'end sealed to said anode, a ring-shaped member having an outer flange extending parallel to the longitudinal axis of said electron discharge device and sealed to the other end of said insulating collar and having an inner flange extending Iparallel to the longitudinal axis of said elec- H tron discharge device'but in the opposite direction from said outer flange, a tubular lead-in and support extending through said ring-shaped member and supporting a cathode, said tubular lead-in and support being sealed to the inner flange of said ring-shaped member, said tubular lead-'in and support being sealed at its end opposite from said cathode, a heater within said cathode having one end connected to said cathode and having a lead connected to its other end, said lead extending through and insulating-ly sealed to said tubular lead-in and support, and a grid positioned between the cathode and the anode having a cone-shaped skirt and supporting element for supporting said grid and havingits smaller end connected to'said grid and its other end connected to said ring-shaped member intermediate said anges.

19. An electron discharge device having a cupshaped anode, an annular member of U-shapecl transverse section sealed on the outside of said cup-shaped anode and adjacent the open end of said anode, a collar of insulating material having one end sealed to the outer rim of said U-shaped member, a ring-shaped member having an outer flange extending parallel to the longitudinal axis of said electron discharge device and sealed to the other end of said insulating collar and having an inner flange extending parallel to the longitudinal axis of said electron discharge device but in the opposite direction from said outer flange, a tubular lead-in and support extending through said ring-shaped member and supporting a cathode, said tubular lead-in and support being sealed to the inner iiange of said ring-shaped member, said tubular lead-in and support being sealed at its end opposite from said cathode, a heater within said cathode having one end connected to said cathode and having a lead connected to its other end, said lead extending Vthrough and insulatingly sealed to said tubular lead-in and'support, and a grid positioned between the cathode andA the anode, and a coneshaped supporting element for supporting said grid and having one end connected to said grid and the other end connected to said ring-shaped member intermediate said flanges and a flat ring secured to the ring-shaped'member on the outside thereof.

20. An elec-tron discharge device having an anode provided with a closed end and an open end, a ring member of U-shaped transverse section sealed to the outside of and adjacent the open end of said anode, a collar of insulating material having one end sealed to the outer leg of the U-shaped ring member, a ring-like member having an outer flange coaxial with said U-shaped ring member and sealed to the other end ci the insulating collar, an inner ange on said ringlike member coaxial with said outer ange and extending in the opposite direction from said outer ilange, a tubular lead and support extending through said ring-like member and supporting a cathode within said anode, a heater in said cathode having one end connected to said cathode and a lead connected to its other end, and a seal between said inner flange and said tubular lead and support, the outer end of said tubular member being sealed off, and a grid positioned between said cathode and anode and having an outwardly iiared skirt connected to and supported by said ring-like member between the flanges on said ring-like member, an elongated cup-shaped tubular shield having its open end telescoped over the outer end of said tubular lead and support, and a terminal in the end of said shield, the heater lead being connected to said terminal.

2l. An electron discharge device having an vanode provided with a closed end and an open end, a ring-like collar sealed to the outside and adjacent the open end of said anode, a collar of insulating material having one end sealed to the outer` portion of the ring-like collar, a ring-like member having a flange sealed to the other end of said collar of insulating material, an inner ange on said ring-like member, and a tubular lead and support extending through said ringlike member and coaxial therewith and supporting an electrode' within said anode, and a seal between said ring-like member and said tubular lead and support, said tubular lead and support being sealed oif.

22. An velectron discharge device having an Y anode provided with a closed end and an open end, a rst ring member sealed to the outside oi and adjacent the open .end of said anode and extending outwardly therefrom, a collar of insulating material having one end sealed to the outer periphery of the ring-like member, a second ring member having an outer periphery coextensive with the outer periphery of said first ring member and sealed to the other end of said collar of insulating material, an inner flange on said second ring'niember coaxial with said anode and extending in the opposite direction from said anode, a tubular lead `and support extending through said second ring member and supporting a cathode within said anode, and a seal between said inner ange and said tubular lead and support, said tubular lead and support being sealed off, and a grid positioned between said cathode and said anode and havin-g a supporting skirt connected to and supported by said second ring member.

23. An electron discharge device having a cupshaped anode, a collar of insulating material lhaving one end sealed to said anode, a ringshaped mein-ber having a ila-nge sealed to the other end of said insulating collar and having an inner flange extending parallel to the longitudinal axis of said electron discharge device but in the opposite direction from said anode, a tubular lead-in and support extending through said ringshaped member and supporting a cathode, said tubular lead and support being sealed to and supported by the inner flange of said ringshaped member, said tubular lead-in and support being sealed at a point remote from said cathode, a heater within said cathode having one 13 end connected to a, lead, said lead extending through and insulatingly sealed to said tubular lead-in and support, and a grid positioned between the cathode and anode and having a. skirt supporting said grid, said skirt being connected to said ring-shaped member.

LEON S. NERGAARD.

REFERENCES CITED The following references are of record in the flle of this patent:

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